Mattress assemblies are known having a supplement mattress attached to a main mattress. The supplement mattress is provided on the main mattress by sewing, either at the factory or by any other known industrial process. This has the disadvantage that this type of mattresses only provides a double bed.
In addition, known mattresses are currently made from standard patterns as regards to size, with bed frames, canapés, or upholstered bed bases being manufactured in the same way in coincidence with the standard size of the mattress. This has the disadvantage that when a larger mattress surface is needed it is necessary to replace it and, in addition, to replace the corresponding bed frame, canapé or upholstered bed base. Such replacement may not be possible in many cases since the lack of space may prevent a mattress from being replaced with a larger one.
A further disadvantage is that the mattresses do not have standard safety barriers for preventing the user from falling to the ground, especially when it comes to young children, elderly, disabled and dependent persons.
Sheets are also known having adjustment mechanisms for adjusting them on a conventional mattress. Known sheets have the disadvantage that when the size or particularities of the mattress are not conventional as stated above, known sheets could not be adapted to some mattress configurations.
Therefore there is a need to provide a mattress assembly which allows its surface to be expanded and, in addition, which is capable of providing the user with a safety barrier for preventing her/him from falling to the ground.